Mask



FIG. 1 is a perspective view of the mask;

FIG. 2 is a front view of the mask;

FIG. 3 is a back view of the mask;

FIG. 4 is a left side view of the mask;

FIG. 5 is a right side view of the mask;

FIG. 6 is a top view of the mask; and,

FIG. 7 is a bottom view of the mask. 

The ornamental design for a mask, as shown. 